1. Field of the invention
The present invention pertains generally to mounting a printed circuit board onto a surface.
2. Description of the Background
Electric and electronic apparatus using printed circuit boards for mounting electrical components have generally required mounting the boards into cases to prevent mechanical damage and to provide electro-magnetic isolation in the form of a Faraday shield. The board must be securely mounted into the case and also have a stand-off to avoid any contact between the components mounted on the board and the case. In order to meet these requirements in the past has required complicated assembly parts, expensive cases, and laborious assembly procedures.
Prior techniques have included using card cage type assemblies. Card cage assemblies typically require mounting slide guides onto the housing. The assembler must work inside the housing using tools and fasteners, for example screws and screwdrivers. An alternative is a housing design which is in an open position during assembly. This requires a more complicated housing design. That type of design complicates the assembly process and the manufacturability design and consequently, the cost of the housing.
Other techniques have included fastening the board directly to the housing. This technique involves the same assembly constraints as the card cage assemblies. Assemblers must either work in a confined space in the housing using tools and fasteners or a relatively complicated housing must be designed and built which allows assembly in an open position and closes after assembly.
Still another technique has been to fasten a printed circuit board onto a rail using screws. One prior technique was a slide member having a support portion and a rail portion connected thereto. The support portion has a threaded cavity for holding a screw, the screw being aligned through a hole in a printed circuit board and the threaded cavity of the support portion so that the printed circuit board is attached to the slide member. The rail portion has a slide surface and an engaging surface, the rail portion having a length. A claw attached to the housing received the slide member and guided the slide member, in order to make contact to the engaging surface of the rail portion, and to secure the slide member to the housing in all directions except along the rail portion length. The rail, in turn, was fastened to the housing by a claw stamped and bent from the housing. The claw allowed the rail to slide along the length of the rail and the length of the housing surface while retaining the rail from moving along the other two axis, side-to-side and up-and-down. This has limitations in that generally at least four, and usually six, screws are required and must be manually attached. At least two rails are needed. Since there are multiple rails, the rails need to be carefully aligned so that the rails are parallel to each other and spaced correctly in order to fit into the claws in the housing.
The problem is to provide a board mounting into a housing design which essentially eliminates the need for assemblers to work in a limited space using tools and fasteners, reduce the number of parts required for mounting a board into a housing, and keep the housing design simple so as to make it easy to fabricate, and reduce its cost.